From 4321b36c97b16bf0e139924df82ddc4520028b9c Mon Sep 17 00:00:00 2001
From: Matt Brophy <matt@brophy.org>
Date: Tue, 11 Jul 2023 15:23:52 -0400
Subject: [PATCH] Add unit tests for header mutual exclusivity

---
 .../__tests__/data-test.ts                    | 174 +++++++++++++++++-
 1 file changed, 172 insertions(+), 2 deletions(-)

diff --git a/packages/remix-server-runtime/__tests__/data-test.ts b/packages/remix-server-runtime/__tests__/data-test.ts
index 5b64f3c7118..01eabf1781e 100644
--- a/packages/remix-server-runtime/__tests__/data-test.ts
+++ b/packages/remix-server-runtime/__tests__/data-test.ts
@@ -1,4 +1,5 @@
 import type { ServerBuild } from "../build";
+import { defer } from "../responses";
 import { createRequestHandler } from "../server";
 
 describe("loaders", () => {
@@ -39,7 +40,133 @@ describe("loaders", () => {
     expect(await res.json()).toMatchInlineSnapshot(`"?foo=bar"`);
   });
 
-  it("sets header for throw responses", async () => {
+  it("sets X-Remix-Response header for returned 2xx response", async () => {
+    let routeId = "routes/random";
+    let build = {
+      routes: {
+        [routeId]: {
+          id: routeId,
+          path: "/random",
+          module: {
+            async loader() {
+              return new Response("text", {
+                status: 200,
+                headers: { "Content-Type": "text/plain" },
+              });
+            },
+          },
+        },
+      },
+      entry: {
+        module: {
+          handleError() {},
+        },
+      },
+      future: {},
+    } as unknown as ServerBuild;
+
+    let handler = createRequestHandler(build);
+
+    let request = new Request(
+      "http://example.com/random?_data=routes/random&foo=bar",
+      {
+        headers: {
+          "Content-Type": "application/json",
+        },
+      }
+    );
+
+    let res = await handler(request);
+    expect(res.headers.get("X-Remix-Response")).toBeTruthy();
+    expect(res.headers.get("X-Remix-Error")).toBeNull();
+    expect(res.headers.get("X-Remix-Catch")).toBeNull();
+    expect(res.headers.get("X-Remix-Redirect")).toBeNull();
+  });
+
+  it("sets X-Remix-Response header for returned 2xx defer response", async () => {
+    let routeId = "routes/random";
+    let build = {
+      routes: {
+        [routeId]: {
+          id: routeId,
+          path: "/random",
+          module: {
+            async loader() {
+              return defer({ lazy: Promise.resolve("hey!") });
+            },
+          },
+        },
+      },
+      entry: {
+        module: {
+          handleError() {},
+        },
+      },
+      future: {},
+    } as unknown as ServerBuild;
+
+    let handler = createRequestHandler(build);
+
+    let request = new Request(
+      "http://example.com/random?_data=routes/random&foo=bar",
+      {
+        headers: {
+          "Content-Type": "application/json",
+        },
+      }
+    );
+
+    let res = await handler(request);
+    expect(res.headers.get("X-Remix-Response")).toBeTruthy();
+    expect(res.headers.get("X-Remix-Error")).toBeNull();
+    expect(res.headers.get("X-Remix-Catch")).toBeNull();
+    expect(res.headers.get("X-Remix-Redirect")).toBeNull();
+  });
+
+  it("sets X-Remix-Redirect header for returned 3xx redirect", async () => {
+    let routeId = "routes/random";
+    let build = {
+      routes: {
+        [routeId]: {
+          id: routeId,
+          path: "/random",
+          module: {
+            async loader() {
+              return new Response("text", {
+                status: 302,
+                headers: { Location: "https://remix.run" },
+              });
+            },
+          },
+        },
+      },
+      entry: {
+        module: {
+          handleError() {},
+        },
+      },
+      future: {},
+    } as unknown as ServerBuild;
+
+    let handler = createRequestHandler(build);
+
+    let request = new Request(
+      "http://example.com/random?_data=routes/random&foo=bar",
+      {
+        headers: {
+          "Content-Type": "application/json",
+        },
+      }
+    );
+
+    let res = await handler(request);
+    expect(res.headers.get("X-Remix-Redirect")).toBeTruthy();
+    expect(res.headers.get("X-Remix-Error")).toBeNull();
+    expect(res.headers.get("X-Remix-Catch")).toBeNull();
+    expect(res.headers.get("X-Remix-Response")).toBeNull();
+  });
+
+  it("sets X-Remix-Catch header for throw responses", async () => {
     let loader = async ({ request }) => {
       throw new Response("null", {
         headers: {
@@ -75,7 +202,50 @@ describe("loaders", () => {
     );
 
     let res = await handler(request);
-    expect(await res.headers.get("X-Remix-Catch")).toBeTruthy();
+    expect(res.headers.get("X-Remix-Catch")).toBeTruthy();
+    expect(res.headers.get("X-Remix-Error")).toBeNull();
+    expect(res.headers.get("X-Remix-Redirect")).toBeNull();
+    expect(res.headers.get("X-Remix-Response")).toBeNull();
+  });
+
+  it("sets X-Remix-Error header for throw error", async () => {
+    let routeId = "routes/random";
+    let build = {
+      routes: {
+        [routeId]: {
+          id: routeId,
+          path: "/random",
+          module: {
+            async loader() {
+              throw new Error("broke!");
+            },
+          },
+        },
+      },
+      entry: {
+        module: {
+          handleError() {},
+        },
+      },
+      future: {},
+    } as unknown as ServerBuild;
+
+    let handler = createRequestHandler(build);
+
+    let request = new Request(
+      "http://example.com/random?_data=routes/random&foo=bar",
+      {
+        headers: {
+          "Content-Type": "application/json",
+        },
+      }
+    );
+
+    let res = await handler(request);
+    expect(res.headers.get("X-Remix-Error")).toBeTruthy();
+    expect(res.headers.get("X-Remix-Catch")).toBeNull();
+    expect(res.headers.get("X-Remix-Redirect")).toBeNull();
+    expect(res.headers.get("X-Remix-Response")).toBeNull();
   });
 
   it("removes index from request.url", async () => {